Shutter for moving-picture projectors



Nov. 5, l 929. H. c. MARKHAM SHUTTER FOR MOVING PICTURE PROJECTORS Filed April 192a liiil Patented Nov. 5, 1929 UNITED STATES PATENT OFFICE HENRY C. MARKHAM, OF HOUSTON, TEXAS, ASSIGNOR OF ONE-HALF TO WILL HOB- WITZ, OF HOUSTON, TEXAS SHUTTER FOR MOVING-PIOIURE PROJECTORS Application filed April 7,

My invention relates to an improvement in shutters or dowsers employed with a moving picture projecting apparatus.

It is an object .of the invention to provide a shutter which may be electrically controlled and which will operate rapidly and silently.

It is also desired that the device be simple in its construction and be adapted to be positively controlled in both opening and shutting the device so that there will be no failure of operation.

In the drawin herewith, Fig. 1 shows a front elevation o the improved shutter with the operating mechanism thereon, the housing being broken away for greater clearness.

Fig. 2 is a side view of the device shown in Fig. 1, the u per portion of the housing being partially roken.

Fig. 3 is a top plan view of the device; and,

Fig. 4 is a broken vertical section centrally of the device illustrating the manner in which the shutters are held frictionally together.

The device is adapted for electrical operation and is mounted upon a housing 1, which encloses some of the actuating mechanism. The shutter itself is mounted upon the hous ing 1 and is made up of a shield 5 of approximately oval shape and having a central opening 2 therein spaced somewhat toward the upper part of the shield. The lower end of the shield is extended laterally on each side in opposite directions to form a base 3 having openings therein to receive cap screws 4 by means of which the screen may be secured to the housing 1. This shield may be of any light, fireproof material, either metal or mica or fiber, as may be desired.

The shutters employed to close the opening 2 throu h the shield are of a somewhat semiovoid i orm and are illustrated at 6 in the drawing. Said shutters are mounted one on one side of said shield and one on the other and on opposite sides of the opening 2. They are pivoted at their inner ends upon a shaft made up of a central threaded pin 7 extending through the shield and having caps 8 screwed on the ends thereof, said caps hearing at their inner ends against the shield, as shown particularly in Fig. 4. These caps serve as a mounting for spiral compression 1928. Serial No. 268,116.

springs 9 bearing against washers 10 and tending to hold the shutters and the shield in proper parallel position. Washers similar to those at 10 are placed between the shield and the shutters so that they will be retained in a position spaced apart as will be noted from Fig. 4. The washers 10 are of metal, such as brass, the shutters 6 being preferably of light, fireproof material such as mica. The inner edges of the shutters shown at 11 are formed on a straight line so that when they are thrown into upper position closing the opening 2, their edges will overlap slightly, as indicated by the dotted lines in Fig. 1.

Each of the shutters is secured to the washers 10 on each side thereof so that the shutter, together with the two washers, are rotatable upon the cap 8 as a unit, the assembly of the shutter and the washers being held frictionall(y against the central shield by the spring 9.

onnected to the outer washer 10 on each of the shutter blades is a link 12, said link being connected to a short crank pin 13 on the washer. The lower end of the link 12 is connected with the upper end 14 of a core 15. As will be seen from Fig. 4, the links 12 on each of the two opposite shutters are connected to the upper end of said core by means of a transverse pin 16.

The said core 15 may be of approximately cylindrical construct-ion having an outer shell A and a hollow inner chamber with laminated metal 17 therein of magnetic material. The outer shell A may be of some light metal, such as aluminum, the lower end of the chamber 17 being closed by a threaded plug 18.

The core 15 is adapted to fit within a double solenoid having an upper winding 19 and a lower winding 20. These windings are connected through a flexible casing 21 and lead to a controlling means including a switch 22. There is an open space in the line having two terminals 23 thereon, by means of which the device may be connected with an electric circuit which may be automatically operated, if desired. It will be noted that the core 15 may be drawn into position within the solenoid 19 by the energizing of that coil, or it may be drawn into position within the lower solenoid by the energizing of the coil 20, it

being understood that only one of these coils is ener ized at the same time.

In t e operation of my improved device, the position of the blades 8 of the shutters is normally open with the opening 2 unobstructed, as shown in Fig. 1. This position of the blades is accomplished by the energizing of the upper solenoid 19. When it is desired to close the shutters obstructing the 10 opening 2, the lower solenoid will be energized so as to draw the core downwardly, thus, serving through the action of the links 12 to throw the shutters upwardly into closed position. Thus by means of the switch 22 5 either solenoid may be energized so that the core 15 may be shuttled back and forth to move the shutters as desired. The shutters are of light material and are spaced from the sides of the shield 5 and may be thrown quickly into closed position with very little noise. In fact, the device is constructed to be practically noiseless. As the blades of the shutters are opened positively and closed positively, the action of the shutter is reliable and the device is found to work Without any failure at all times. The device is, therefore, light in construction and noiseless in its operation and the shutters may be positioned positively in either closed or opened position in the manner shown. It is to be noted also that each of the washers 10 have on their lower sides a notch, indicated at 24, which receives therein a projection 25 upon the base 3. In this manner, the movement of the blades of the shutter is limited both as to opening and as to closing action. This assures the operator that the blades will stop in closed position, overlapping as indicated in Fig. 1. The further advantages of the device will be obvious to those skilled in the art.

What I claim is: 1. In a device of the character described, a housing, a shield thereon having an opening therethrough, a pair of opposite shutter blades pivoted at one side of said opening upon said shield, disc-shaped washers secured to said blades about the pivot, means to hold said washers frictionally against said shield, and means to move said blades to and from position closing said opening.

2. In a device of the character described, a housing, a shield thereon having an opening therethrough, a pair of opposite shutter blades pivoted at one side of said opening upon said shield, disc-shaped washers secured to said blades about the pivot, means to hold said Washers frictionally against said shield, and means secured to said washers to move said blades to and from position closing said opening.

3. In a device of the character described, a housing, a shield thereon having an opening therethrough, a pair of opposite shutter 65 blades pivoted at one side 0 said opening upon said shield, disc-shaped washers secured to said blades about the pivot, means to hold said washers frictionally against said shield, and means to move said blades to and from position closing said opening including a core aving magnetic material therein, links connecting said core and said washers, and means to move said core to operate said blades.

4. In a device of the character described, a housing, a shield thereon having an opening therethrough, a pair of opposite shutter blades pivoted at one side of said opening upon said shield, upper and lower solenoids in said housing, a core slidable in said solenoids, and links connecting said core operatively with said blades, said core being moved to open or close said blades by the selective energizing of said solenoids.

5. In a device of the character described, a housing, a shield thereon having an opening therethrough, a pair of opposite shutter blades pivoted at one side of said opening upon said shield, disc-shaped washers secured to said blades about the pivot, means to hold said washers frictionally against said shield, links connected operatively with said washers, a magnetic core engaged with said links, and electro-magnetic means arranged to move said core to a plurality of positions to operate said shutter blades.

6. A shutter comprisin 'a shield, having a light opening therethroug a pivot ad'acent said opening on said shield, a pair of s utter blades, one on one side of said shield and one on the other mounted to swing on said pivot to close or clear said opening, means on said blades frictionally en aging said shield and adapted to retain said lades in adjusted position, and means engaging said blades to move them relative to said openin 7. A shutter comprising a 'shie d, having a light opening therethrou h, a pivot adjacent said opening on said shieId, a pair of shutter blades, one on one side of said shield and one on the other mounted to swing on said pivot to close or clear said opening, a solenoid, a core therein, and means connecting said core and said blades whereby the movement of said core will move said blades in the manner described.

8. A dowser for projection machines in cludin in combination a pair of co-operating pivoted blades, an ovoid shield disposed between said blades, a magnetic core connected with and ada ted to actuate said blades, and a pair of so enoids arranged to positively move said core to operate said blades.

9. A dowser for projection machines including in combination a support, a shield mounted thereon, a pivot pin carried by said shield, a pair of dowser blades mounted on opposite sides of said shield and upon said pin, and co-engagin means on said blades and said support to 't the pivotal movement of said blades.

10. A dowser for projection machines including in combination a support, a shield mounted thereon, a. pivot in carried by said shield a pair of dowser lades mounted on opposite sides of said shield and upon said pm, co-engaging means on said blades and said su port to limit the pivotal movement of saidh ades, and resilient means carried by said pin to retain said blades in aligned position.

m In testimony whereof I hereunto aflix my signature this 3rd da of A ril, A. D. 1928. HE RY MARKHAM. 

